What is (a) A dislocation of the strata of the vein. (b) In coal seams, coal rendered worthless by impurities in the seam; as, slate fault, dirt fault, etc. Raymond called?

fault — (Geol. & Mining) (a) A dislocation of the strata of the vein. (b) In coal seams, coal rendered worthless by impurities in the seam; as, slate fault, dirt fault, etc. Raymond. (Webster's 1913.)

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